This invention relates to medical instruments. More particularly, this invention relates to an apparatus for automatically counting the number of times a medical or surgical instrument has been sterilized. The invention finds particular use in endoscopic surgical instruments which should be disposed of after a certain number of uses.
Endoscopic surgery is widely practiced throughout the world today and its acceptance is growing rapidly. In general, endoscopic surgery involves one or more incisions made by trocars where trocar tubes are left in place so that endoscopic surgical instruments may be inserted through the tubes. A camera or magnifying lens is often inserted through the largest diameter trocar tube (e.g. 10 mm diameter), while a cutter, dissector, or other surgical instrument is inserted through a smaller diameter trocar tube (e.g. 5 mm diameter) for purposes of manipulating and/or cutting the internal organ. Sometimes it is desirable to have several trocar tubes in place at once in order to receive several surgical instruments. In this manner, organ or tissue may be grasped with one surgical instrument, and simultaneously may be cut with another surgical instrument; all under view of the surgeon via the camera in place in the larger trocar tube.
By 1996, it is expected that more than two million additional endosurgeries will be performed per year that, in 1990, were done via open surgery (MedPRO Month, I:12, p.178). The advantages of endoscopic surgery are clear in that it is less invasive, less traumatic and recovery is typically quicker. As a result, many new instruments and devices for use in endosurgery are introduced every year. Most endoscopic instruments have similar configurations with a proximal handle, an actuation mechanism, and distal end effectors coupled by a tube through which the actuation mechanism extends. The end effectors take many forms such as grippers, cutters, forceps, dissectors and the like. Some endoscopic instruments are provided with a ferrule on the tube so that the tube which carries the end effectors can be rotated relative to the handle. Initially, endoscopic surgical instruments were very expensive, partly because they must be very small but still durable and reliable and the materials necessary to provide these features are expensive.
Recently, a number of "disposable" endoscopic instruments have been introduced and their use is now widely accepted. One of the advantages of disposable endoscopic instruments over reusable instruments is that because they are used only a single time, there are no sterilization problems, and no concerns about the dulling or nicking of blades or wearing of parts. However, in order to justify disposing of instruments after a single use, the instruments have to be much less expensive than the reusable tools. In order to manufacture the instruments less expensively, the disposable instruments therefore use less expensive materials. As a result, the disposable instruments are less durable than the reusable instruments, which is not of concern where the instruments are used only once. However, in order to reduce the costs of medical procedures, many hospitals and surgeons have recently started to sterilize and reuse the "disposable" endoscopic instruments. This practice can be problematic. While the disposable endoscopic instruments typically are not so fragile that they must be disposed of after a single use, clearly, they may not be used as many times as the typical stainless steel reusable instruments as they are more likely to malfunction and dull after several uses. Presently, there is no scientific mechanism available for determining how many times a medical instrument has been used, and the surgeon or the surgical staff must devise their own system to keep track of the number of times a tool has been used so that it will not be used after its useful life has expired.